Fuel control apparatus for internal combustion engines



April 28, 1942. J cAMPBELL 2,281,411

FUEL CONTROL APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed March 2, 1938 4 Sheets$heet 1 IN VEN roR JOHN f. CAMPBELL 22 "ZZBY E aw .y g-,

A r roRlvz YS April 28, 1942- J. F. CAMPBELL FUEL CONTROL APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed March 2, 1938 4 Sheets-Sheet 2 A TTOIPIVE'YS P 1942- J. F. CAMPBELL FUEL CONTROL APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed March 2, 1938 4 Sheets-Sheet 3 R u m M N P E M v A M C F N H O J 3 mm M ag xv iv April 28, 1942.

J. F. CAMPBELL 2,281,411 FUEL. CONTROL APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed March 2, 1938 4 Sheets-Sheet 4 J06!) fi'C'qmpia/Z INVENTOR Patented Apr. 28, 1942 UNITED STATES PATENT OFFICE FUEL CONTROL APPARATUS FilR 17 i TEHNAL CGMBUSTION ENGINES John F. Campbell. Dayton, Ohio, assignor to George M. Holley and Earl Holley Application March 2, 1938, Serial. No. 193,598

11 Claims. (Cl. BBL-3E3) It is the object of this invention to provide ferentials in air pressure and which may be sub means and method of controlling the operation stituted for the Venturi ilill lh "w n in Figures of an internal combustion engine, particularly an 1 and 2. aircraft engine, by utilizing the mass of air which Figure 4 ilisiiaiss ii iii" e control mesh is flowing to regulate fuel flow. 5 anisrn employed in the 5:5 trams shown in Fig- It is a further object to use a venturi. orifice, tires 1 and 2, and which l'llW'llCilil Sill is controlled nozzle or similar instrumentality to obtain an by the mass air flow from the Venturi air conindication of the mass of air which is flowing by trolling means. By the functioning of the appawhich fuel flow is regulated. ratus, an oil servo operated piston is caused to The mass of air flowing into an internal comoperate by reason of the changes in mass air hustion engine is indicated, as it varies, by the flow to regulate the fuel delivered to correspond differential in pressure caused by change in V9- to that ratio of fuel and air previously establocity beiwcen a main air body flowing into the lished as desirable for the particular engine for engine and a by-pass body also flowing into the that particular mass air dew and air density. engine, which by-pass body is passed through 16 Figure 5 is a top plan VlfW of the bellows comsome restricted orifice, such as a venturi, pcr- Densator known as the air cam and density corforated plate. or the like. rection metal hollows.

It is an object of this invention to utilize this Figure 6 i a s i n n h l 6 -6 h w n velocity principle in order to control fuel delivthe contour of the cam when the I Lui'i is corn= cry to the engine. 20 pensatc l for density changes.

It is an bj t of thi invenfign t provide a Figure '7 is a section on the same line showfuel t a proporti nlng means comprising ing the contour of the cam when th venturi is a fuel indicator, an air and fuel adjusting means riot compensated f r n lr han s. and a fuel control means. It is also an object to Figure 8 s fi fl 0n the line 3 -3 01' i provide in combination therewith a differential ure 5 showin h n ur of the cam when the pressure means controlled by the mass air flow 191161111 cflmpellfiateii for density 868- and including a proportioner which controls the Figure 9 is a section on the line 8-8 of Figfluid supply and is operated in accordance with UTE 5 wing the contour of the cam when the the pressure differential venturi is not compensated for density changes.

It is a further object to provide in combination Figure 10 illustrates a m dified form of Ventherewith means for supplying, or injecting, the tube which may be Substituted o that luel. shown in Figures 1 and 2. In this modified 1; is an j t, {0 provide a venturi comPen- Venturl tube. the pressure differences inside of aflng means t Cgmpensate for change in air and outside of the venturi indicate mass air conlensity, that is, changes due to temperature var- Sumptifin at Various a ens ties. aflons and prgssure variagions Figure 11 illustrates still another form of Venished the engine is regulated by nm the i suction nozzle into a larger area where the sucitput from a fuel transfer pump and in which tion is 153$ r is introduced into a pipe of the mdum Figure 12 shows in one view the device illus- 3n system common to n Cylinders thereon trated diagrammatically in Figures 1, 4 and 5. T form f my invention operates upon t This invention is particularly adaptable to airinciple that the differential between the mass craft n in s. although it is of en l utili y. air flowing in the induction pipe and in a The p le upo W ch I e t p ion nturi is used to regulate the amounto! fuel of the method and apparatus of my invention rnished by the fuel metering and distributing is this: h lum f ir p sin hro h a it channel in which a venturi is mounted is propor- Figure 2 shows a system similar to Figure 1 tional to fii l l where Pilpressure in the I: employing a fuel nozzle for introducing the channel and Pz"pI'E5sLli-o at the throat of the ii eparatel into each cylinder, veniuri. Also as long as ihcair density in the igure 3 diagrammatically illustrates a dilferchannel remains constant ti e mass air flow is form of restricted orifice for determining difproportional to v'Pi Pi However when the air density decreases and the speciflcyolume of the air increases, for a given mass of air flowing through the channel, \/P1-Pz increases in direct proportion to the density change.

Referring to the drawings in detail, I designates generally an internal combustion engine of the multiple cylinder radial type, which drives a hub 2 on which are mounted suitable blades of a propeller.

In Figure 1 there is a common air suction inlet pipe 3 in which is mounted a. venturi 4 constituting an auxiliary passageway or'by-pass. The suction pipe 3 has connected thereto a pressure differential pipe 5 in advance of the venturi which is connected to the differential control and proportioner mechanism generally designated 5. This pipe 5 is connected into 5 at I. The pipe 5 leading from the venturi is connected into B at 9. Fuel is supplied either from the main fuel tank ill through pipes II and I! or from the supplementary or emergency tank I! through the pipe i4.

This fuel supply is controlled through the valve i5 to the filter I5 and thence through the pipe H to the engine driven pump IS.

A by-pass comprising pipes I! and 20 is provided through the hand pump ii. The by-pass through the pipes 22 and 23 is controlled by the valve 24 which is a yessure regulator valve. This pressure regulator valve is controlled by a valve lever 25 pivoted to 25, connected through a pitman 21 to the piston rod 28 attached to the piston 29 (Figure 4) operating the cylinder 30, which is the fuel control means hereinafter described.

When this piston rod 28 moves downwardly the fuel supply is increased, and when it moves upwardly, it is decreased, so operating in conjunction with the associated servo valve 3!.

Oil under pressure enters through pipe 32 and passes through passageway 33, and thence through return oil passageway 34 and pipe 35. It also can pass through the distribution passageway 36, 31 and 38, as it is controlled by the valve 31 to control the entry of the oil to either end of the cylinder 30 through the passageways 39 and 40. The pressure lines 32 and 35 are connected into the oil reservoir system of the engine generally designated 4|.

Returning to the engine driven pump ill, or hand pump 2|, the fuel proceeds under pressure through the pipe 42, vapor eliminator 43 to the compensator 6 whence the fuel passes through the passageway 44 (Figure 4) as indicated by the direction of the arrow through the Venturi throat 45. pipe 45 and thence by pipe 41 (Figure 1) to an injector spray nozzle 48 over which the incoming air passes. This may be the nozzle of any form of carburetor or fuel supply device.

Such is the general operation of the system. The differential between the pressure condition in pipe 5 (P1) and the pressure in pipe 8 (P2) is utilized to compensate for the change in air density, due to changes in temperature and pressure.

As will be seen in Figure 3, instead of a venturi. a plate 4a with an opening 4!) may be interposed in the suction line 3. This suction line is also controlled by the usual butterfly valve 40.

The details of the venturi are shown in Figures and 11. The system shown in Figure 2 is similar to that described in connection with Figure 1, except that a valve illl is employed to control the fuel to the pipe 41a.

Turning to the o1 shown in Figizire 4, whir' i1: which is being viewed from an opposite side of the engine as shown in Figures 1 and 2, it will be understood that the fuel is flowing through the passageway as. A Ilfli'loi this fuel is pa through the restricted passageway 49 in front of the piston 50 in the cyinder 5i. This piston is normally pressed towards the left end by the Spring 52. Fuel is d liv re 1) iii; right the piston 50 through the passageway 53 whic is on the outgoing side of the venturi 45 and the fuel line 44--46. The piston rod 54 which is connected to the piston 52 is pivotally connected to a cam 55 guided in the guide ways 58 in the chamber 51. There rides on this cam a cam follower 58 mounted on the bell crank having arms 59, said bell crank being pivoted at fill. A coil spring 90 is arranged to keep the cam follower 58 in engagement with the cam surface 55. The free end of the bell crank is slotted at 5! and is connected with a pitman 62 that is slid-- ably supported in the passageway 63 in the par tition 64. The other end of this pitman is con nected by a pin 65 into a slot 66 in a compensating T-shaped member 61. The T portion of 61 is designated 68, and is provided with an elongated slot 69 in which operates the pin in on the upper end of the valve 3!. The lower end of this T-shaped member is pivotally connected at 11 to a second pitman 12 connected with the differential air system to be hereinafter described.

Now turning to the differential air system. the pipe 5 (Pi) is connected to the cylinder I3 (Figure 4). This connection is on the left end of the air piston 14. A passageway I5 establishes communication between 13 and the chamber 16. On the right end of the piston 14 there is a chamber 11 connected to the venturi pipe 9 (P2). A spring 18 tends to move the piston 14 to the left end. The piston 14 is connected by its piston rod 19 to the cam block 80. This cam is cam shaped in two directions longitudinally and transversely as indicated by the dotted lines and the Views 5 to 5 inclusive.

This cam block is mounted in a guide Bi, which in turn is mounted upon a transverse slide 82 having a dove-tail engagement with the base 84. There is connected to this base a barometric metal bellows B5 anchored to the casing 5 at one end and connected by the connector 81 at its other end to the support 82. In this manner, the cam is adapted to move laterally as well as longitudinally to accommodate this. The piston rod 19 is slidably mounted upon a cam cross rod 19a carried between the jaws 19?) (Figure 5) mounted on the left hand end of the cam 80. A cam follower 83 rides upon the cam sur face 84. This cam follower is mounted on the bell crank arm 85a pivoted at 86, the other arm of which, 8111, is loosely pivoted to the pitman 12 heretofore mentioned. A coil spring 89 is provided to keep the cam follower 83 in contact with the cam surface 84.

In Figures 6 to 9 will be seen sections through the cam 80 indicating the differences in contours of the cam, depending upon whether the venturi (Pl-P2) is compensate; for density changes.

The difference in pressure between the mass of air flowing in the intake manifold 3 and in the venturi 4 is transferred to the piston 14 through the opening 1 Pi) and 8 (P2). The movement of this piston 14 and the attached cam is proportional to VPT PEL With knowledge of the engine mixture strength required, the cam 80 is so designed that the vertical height of its contour represents the fuel required for the corresponding air consumption. As illustrated each .050" lift represents ten per cent fuel consumption. In order to compensate for the fuel consumption required by'the engine when operating at various altitudes, or air densities, cam 80 is moved horizontally by the gas filled metal bellows 85, which changes its length in proportion to density changes. The contour of cam 80 is varied in the transverse direction to compensate for the variation in fuel consumption needed for the engine due to variationsin air density which vary with the altitude. The lift of the cam is transferred through the bell crank arms 85:1-81 to the pitman 12 so that the position of this pitman represents the fuel consumption required for any mass air consumption at any air density.

Turning to the mechanism which furnishes an indication of the fuel consumption actually being used by the engine, the pressure differences between the pressure in pipe 44 and in pipe 49, as compared with the pressure in pipe 53 on the other side of venturi i5, is utilized to affect piston 50 which in turn moves cam 55. Each .050" lift of this cam represents ten per cent fuel consumption, This lift is transferred into horizontal motion of the pitman 62,

Any difference between the fuel consumption the engine is actually getting (position of pitman 62) and that which it should be receiving (position of pitman 12) for any particular air consumption or air density, causes the servo valve 3| to rise or fall depending upon which way the factor of out of balance occurs. A rise of the servo valve 3| will cause the piston 28 to lower, which will decrease the fuel consumption of the engine, as is indicated by the layout of the system in Figures 1 and 2. A lowering of the servo valve 3| will increase the fuel consumption.

The oil from the oil pressure system of the engine circulated to and from the servo valve ill by the pipes 32 and 35 is merely a pressure medium used to move the piston 29 and piston rod 28, which in turn throiigh the linkage 21 and 25 (Figure 1) controls the amount of fuel supplied by moving the valve 24.

Turning to the Venturi compensators shown in Figures and 11, Figure illustrates the venturi l with a Pitot tube II, which communicates with a chamber 80 in which is mounted a metal bellows 90. The expansion of this bellows is resisted by the spring 9'. The bellows is connected through the piston rod 92 which is guided by the guide 93 to a piston valve 94 which controls the size of the passageway I. The chamber 89 is connected to the pipe 8. In this manner the contour valve 94 is positioned according to the air density through the metal bellows to supply a sufficient bleed through 5 (P1) to 8 (P2) to: offset the increase in MP1) to 8 (2 which otherwise would occur.

In Figure 11, the tube ll connecting with wer chamber 89 can bring about a movement of the J metal bellows 90 which moves the pipe a foreand-aft together with the slidable plate Mb to which itis secured in order to compensate for reductions in air density. The auction nozzle Na 7 is therefore moved to a larger area-in the venturl 4 where the suction is less.

fuel source, a proportioner or compensator is comprising a fuel supply control means, .11 in air differential adjusting the fuel indicator to coni- 'nsatingly adjust the fuel control means; and there is a mass air differential controlling means connected to said proportioner to regulate the amount of fuel according to the differential in pressure in the main air suction line and the by-pass line, that is, the Venturi line. There is associated with these means some form of fuel injector, or carburetor, the exact nature of which is not important in this invention. Additionally there is provided compensating means to compensate for changes in air density due to changes in temperature and pressure resulting from changes in altitude at which the engine is operated.

Accordingly the mass of air flowing is utilized to regulate the fuel flow by the differential in pressure caused by the change in velocity between the mass of air in the pipe 8 and the venturi or by-pass air body l, which enables the regulation of the fuel flow in proportion to mass air flow to give satisfactory engine performance automatically without the intervention of the operator.

The bellows I5 is located on the walls of the inlet passage 8, and will therefore respond to the temperature of the entering air before it is cooled by the fuel entering through the nozzle 41. The bellows contains sufllcient air so that as the temperature rises the air contained within the bellows expands. In other word, the bellows 86 is a partially exhausted capsule. For this reason the bellows II will respond to temperature and pressure changes.

It will be understood that I desire to compre hend' within my invention such modifications as may be necessary to adapt it to varying conditions and uses.

Having thus fully described my invention. what i claim as new and desire to secure by Letters Patent, is:

1. Fuel control means for an internal combustlon engine comprising an air induction Passagemeans in said passage responsive to air flow .herethrough to provide a diflerential fluid pressure proportional to air flow, a source of liquid fuel under pressure, and a conduit connecting the source with said. induction passage, said fuel conduit including means responsive to fuel flow to provide a differential fluid pressure propor tional to the rate of fuel flow, a device subject to and movable by the air differential pressure, a second device subject to and independently movable by the fuel differential pressure. a now regulating valve controlling the eifective capacity of the fuel conduit, a servomotor for operating said valve, means shiftable by the first device to posh tions determined by the measured rate of air flow, independently movable means shlftable by the second device to positions determined by the measured rate of fuel flow, and linkage means interconnecting the two last named means with the servomotor to move said valve to increase or decrease the capacity of said conduit depending upon whether the measured rate of fuel flow is respectively less or greater than that required to provide a predetermined variable fuel air ratio with the measured rate of air flow.

2. A device as set forth in claim 1 in which the linkage means includes a T-shaped link, and means controlling the servomotor and in which the device movable by the air diflerential pressure and the device movable by the fuel differeneans integrated with" "a tial pressure consist of cams and cam followers, said followers engaging with the extremities of the head of the T-shaped link. the stem of which is connected with the means controlling the servomlotor.

' 3. A device as set forth in claim 1 adapted for aviation use in which is incorporated means responsiye to the static pressure of the air in the induc on passage to modify the reaction of the air fio" means with the fuel flow means to provide a variable fuel air ratio depending both on the rate, of air ow by weight and on the air density.

4. A dev e as set forth in claim 1 in which isincorporated means responsive to the temperature of the air in the induction passage to modify the reaction of the air flow means with the fuel flow means to provide a variable fuel air ratio depending both on the rate of air flow by weight and on the air density.

5. A device as set forth in claim 1 adaptedfor aviation use in which means responsive to the temperature and static pressure of the air in the induction passage modifies the relative positioning of the means responsive to air flow and the means responsive to fuel flow so as to provide a variable fuel air ratio depending both on the rate of air flow by weight and on the air density.

6. A device as set forth in claim 1 in which means responsive to the temperature of the air in the induction passage modifies the relative positioning of the means responsive to air flow and the means responsive to fuel flow so as to provide a variable fuel air ratio depending both on the rate of air flow by weight and on the air density.

7. A device as set forth in claim 1 adapted for aviation use in which means responsive to the static pressure of the air in the induction passage modifies the relative positioning of the means responsive to air flow and the means responsive to fuel flow so as to provide a variable fuel air ratio depending both on the rate of air flow by weight and on the air density.

8. A device as set forth in claim 1 adapted for aviation use in which is incorporated means rcsponsive to the temperature and static pressure of the air in the induction passage to modify the reaction of the air flow means with the fuel flow means to provide 'a variable fuel air ratio depending both on the rate of air flow by weight and on the air density.

9. A device as set forth in claim 1 adapted for aviation use in which the device movable by the air differential pressure consists of a cam having a double curvature and a cam follower engaging therewith and in which there are means responsive to the temperature and static pressure of the air in' the induction passage for moving said cam at right angles to its motion in response to changes in the air differential pressure and in which the device movable by the fuel differential pressure also consists of a cam and cam follower.

it). A device as set forth in claim 1 adapted for aviation use in which the device movable by the air differential pressure consists of a cam having a double curvature and a cam follower engaging therewith and in which there are means responsive to the static pressure of the air in the induction passage for moving said cam at right angles to its motion in response to changes in air differential pressure and in which the device movable by the fuel differential pressure also consists of a cam and cam follower.

11. A device as set forth in claim 1 in which the device movable by the air differential pressure consists of a cam having a double curvature and a cam follower and in which there are means responsive to the temperature of the air in the induction passage for moving said cam at right angles to its motion in response to changes in air differential pressure and in which the device movable by the fuel differential pressure also consists of a cam and cam follower.

JOHN F'. CAMPBELL. 

